LOANS AND ALLOWANCE FOR LOAN LOSSES - Receivables Past Due (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Non-accrual	$ 15,726	$ 18,008
Loans Past Due 90 Days or More and Still Accruing	0	7
Aging of the recorded investment in loans past due [Abstract]
Past Due	22,415	14,370
Loans Not Past Due	1,521,113	1,298,533
Total ending loans balance	1,543,528	1,312,903
30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	15,081	4,672
60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	679	1,668
90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	6,655	8,029
Commercial and agricultural:
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	406,013	230,922
Commercial mortgages:
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	692,935	650,570
Commercial mortgages: \| Construction
Financing Receivable, Past Due [Line Items]
Non-accrual	63	80
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Loans Not Past Due	54,523	44,082
Total ending loans balance	54,523	44,082
Commercial mortgages: \| Construction \| 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Commercial mortgages: \| Construction \| 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Commercial mortgages: \| Construction \| 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Commercial mortgages: \| Commercial mortgages
Financing Receivable, Past Due [Line Items]
Non-accrual	6,027	8,407
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	13,217	2,883
Loans Not Past Due	625,195	603,605
Total ending loans balance	638,412	606,488
Commercial mortgages: \| Commercial mortgages \| 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	11,077	440
Commercial mortgages: \| Commercial mortgages \| 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	262	277
Commercial mortgages: \| Commercial mortgages \| 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,878	2,165
Residential mortgages
Financing Receivable, Past Due [Line Items]
Non-accrual	1,742	2,155
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,074	2,775
Loans Not Past Due	226,910	186,099
Total ending loans balance	227,984	188,874
Residential mortgages \| 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	631	1,016
Residential mortgages \| 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	9	803
Residential mortgages \| 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	434	956
Consumer loans:
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	216,596	242,537
Consumer loans: \| Home equity lines and loans
Financing Receivable, Past Due [Line Items]
Non-accrual	1,017	641
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	346	653
Loans Not Past Due	81,424	91,412
Total ending loans balance	81,770	92,065
Consumer loans: \| Home equity lines and loans \| 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	169	353
Consumer loans: \| Home equity lines and loans \| 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	30	151
Consumer loans: \| Home equity lines and loans \| 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	147	149
Consumer loans: \| Indirect consumer loans
Financing Receivable, Past Due [Line Items]
Non-accrual	604	571
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,156	2,278
Loans Not Past Due	120,564	133,088
Total ending loans balance	121,720	135,366
Consumer loans: \| Indirect consumer loans \| 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	753	1,546
Consumer loans: \| Indirect consumer loans \| 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	190	377
Consumer loans: \| Indirect consumer loans \| 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	213	355
Consumer loans: \| Direct consumer loans
Financing Receivable, Past Due [Line Items]
Non-accrual	1	7
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	206	49
Loans Not Past Due	12,900	15,057
Total ending loans balance	13,106	15,106
Consumer loans: \| Direct consumer loans \| 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	18	32
Consumer loans: \| Direct consumer loans \| 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	187	11
Consumer loans: \| Direct consumer loans \| 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1	6
Commercial and industrial \| Commercial and agricultural:
Financing Receivable, Past Due [Line Items]
Non-accrual	6,272	6,147
Loans Past Due 90 Days or More and Still Accruing	0	7
Aging of the recorded investment in loans past due [Abstract]
Past Due	6,416	5,732
Loans Not Past Due	398,913	224,916
Total ending loans balance	405,329	230,648
Commercial and industrial \| Commercial and agricultural: \| 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	2,433	1,285
Commercial and industrial \| Commercial and agricultural: \| 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1	49
Commercial and industrial \| Commercial and agricultural: \| 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	3,982	4,398
Agricultural \| Commercial and agricultural:
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Loans Not Past Due	684	274
Total ending loans balance	684	274
Agricultural \| Commercial and agricultural: \| 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Agricultural \| Commercial and agricultural: \| 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Agricultural \| Commercial and agricultural: \| 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	$ 0	$ 0

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Amount of financing receivable 90 days or more past due and still accruing.

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